A New Family of Chipsets
To compliment the new Core i5, i3 and Pentium series processors, Intel is also introducing a handful of new chipsets. They all have a number of shared features, but each is targeted at a different market segment.
Because the Core i5, i3 and Pentium series processors series processors feature integrated memory controllers and PCI Express connectivity, in addition to graphics, virtually all of the functionality previously integrated into a northbridge is now on the CPU die or at least on the same package. As such, the new chipsets designed for Clarkdale are fundamentally similar to a southbridge chip, but linked directly to the processor.
The above block diagram shows the new H57 chipset; the H55 is essentially the same, sans a couple of USB and PCIe ports and support for Intel Rapid Storage Technology. As you can see, the chipset links to the processor via a DMI interface in addition to an FDI, or Flexible Display Interface. Memory and some PCI Express expansion cards--most likely graphics card(s)--connect directly to the CPU. The H57 Express itself features 14 USB 2.0 ports, an additional 8 lanes of PCE Express Gen 1 connectivity, and integrated GigE MAC, HD audio, 6 SATA ports, and a number of digital display ports, to accommodate HDMI, DisplayPort, and DVI outputs on the motherboard.
The entire family of new chipsets debuting alongside Clarkdale is outlined in the chart above. The H57 and H55 are targeted at home desktop users, while the Q57 is designed for the enterprise space where features like Anti-Theft and Active Management Technologies are more desirable, and more likely to be used. Overall, the H57 and H55 differ in only three ways. The H57 supports up to 14 USB 2.0 ports, while the H55 supports 12. The H57 has two additional PCI Express 2.0 ports. And the H55 lacks support for Intel Rapid Storage Technology. The P55 is listed in the chart because it is technically compatible with Clarkdale-based processors, but because the P55 lacks the necessary features to expose Clarkdale's integrated Intel HD Graphics core, it's not likely to be popular choice for Clarkdale-based systems.